Tournament favourite Judd Trump has been knocked out of the World Championship by world number 54 Rory McLeod after a remarkable first-round 10-8 defeat.
McLeod, a 46-year-old 1000-1 outsider, led 9-7 when slow play meant the match had to be halted prior to Wednesday's afternoon session.
An out-of-sorts Trump won a scrappy opening frame when their match resumed in the evening, but the Leicester man sealed what he called "the biggest win of his career" to reach the last 16.
Earlier, former world champion Graeme Dott earned a tense 10-7 victory over two-time finalist Ali Carter.
As exciting as the Dott-Carter contest was, it never got close to reproducing the drama between Trump and rank outsider McLeod, who has only previously reached the second round at the Crucible once in his long career.
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Trump, the 2011 runner-up, has reached five major finals this season and was full of confidence about his chances of claiming a first Crucible title in the build-up to snooker's showpiece occasion.
He resumed 5-4 behind on Wednesday after surrendering a 4-0 lead but, despite seeming to be hindered by a shoulder problem, the 27-year-old managed to fight back to 6-6 before McLeod pulled away
McLeod has only qualified for the World Championship three times in his long career.
But his astute matchplay and meticulous approach seemed to disrupt Trump, who was uncharacteristically wayward with his long potting and sloppy with his break building when he did get in the balls.
"It's brilliant. I was relaxed at 4-0. He was potting everything. There is not much you can do so you have to bide your time," McLeod said after the match.
"Maybe I went into zombie mode because I didn't know the score - if it was 4-4 or 5-4.
"I tried not to think about things too much. You have to dismiss the pressure."
McLeod plays Scotland's Stephen Maguire in the second round.
Dott got Carter
Earlier Carter took the opening frame to reduce the overnight gap to 6-4 against Dott and the Essex potter kept nagging away at the qualifier to get back to 8-7.
But Dott edged a pivotal 16th frame when both men wasted good chances and went on to consign Carter to a first last-32 exit since 2006 - the year Dott was crowned champion.
"I love it here," said Dott. "I am not the best at anything, long potting, safety or break building. But I am pretty good at everything, and over the long games that is what you need.
"My season can be absolute garbage and then I come here and I feel like a snooker player."
Robertson in control
Elsewhere, Neil Robertson, the 2010 champion, cruised into an 8-1 lead against World Championship debutant Noppon Saengkham in a match that plays to a conclusion on Thursday.
China's Xiao Guodong beat Ryan Day, the only Welshman who qualified for this year's tournament.
Xiao led 6-3 after the morning session and remained fully in control to ensure there is no Welsh representation in the second round of the World Championship for the first time since 1969.
The other evening match was an all-English encounter with 2013 runner-up Barry Hawkins leading Leicester's Tom Ford 7-2 when play ended for the day.